Cutting mechanism for mowers.



J. S. LYNCH.

CUTTING MEOHANISM FOR BOWERS.

ArrLIoLnoH FILED Ju. 11, 190e.

957,468. Patented May 10,1910

Ill

s. @gmk WITNESSES: INVENTOR /2 JAMEBE. I YN A TTORNE YS tin :ramas s. mYNcH, or errnoNnLLE, ALABAMA.

:maxaman :son u-orwnns.

if. Matutina mea Ianiagyn, isos. serial m1410315.

Tcallwkom'itmyconcelmf' i;

Be it known that I, JAMES S: Lntoaea s citizen ofthe United States o fgAmerica, residing at Citronelle, in the county of Mobile and bftate' of Alabama, have invented oertain new and useful Improvements in Cut- Mechanism for Mowers, of which the fol owing is ya specification, reference being had therein to the accompanying drawings.

This invention relates to a new cutting apparatus for mowers and the object of the invention is to provide cutting mechanism 1n which Athe knife operates with a shearing action.

To this end my invention embodies arevolving knife having a knife edge which forms a plurality of spiral convolutions and` a series of stationary knife guards having knife edges adapted to coperate therewith all in the manner more fully hereinafter described.

In the drawings which accompany this specification, Figure 1 is a plan view partly in horizontal section showing my invention as embodied in a lawn mower. Fig. 2 is a side elevation thereof. Fig. 3 is a cross section on line of Fig. 1. Fig.` 4 is a plan view of a modied construction of cutting mechanism. Fig. 5 is a cross section of Fig. 4. Fig. 6 is a detached perspective view of a section of the stationary knife guards shown in Fig. 4 and Fig. 7 is a detached perspective View of a modified form of revolvingknife.

eferring to the reference numerals on the drawings 1 'is the frame, 2 the internally geared ground wheels and 10 the handle of the lawn mower all of known construction except as more fully hereinafter described. In the front end of the frame is journaled a transverse shaft 3 which carries the revolving knife 4 and this shaft receives motion from the ground wheels through suitable intermediate gear in a manner to cause the knife to rapidly Arevolve in the direction of the arrows shown in Figs. 3 and 5, -which is in a direction op osite to that in which it revolves in the or inary lawn mower.

As` illustrated in the drawings, the transverse shaft 3 carries pinions 5 at the ends which receive motion through intermediate gear wheels 6 from pinions` 7 connected l' therewith through stub shafts 8 and meshing with the internal gear of the ground wheels. The revolving knife 4 is formed similar to a conveyer screw preferably as a continuous sparsi time wah n. .panna of'. convoluswmaam of Letters raient. Patented May 10, 1910. l'

twins, the spiral edge of the lade forming the cutt/ingledge 9 thereof. L.'.llhis knife revolves wit -n .a concave 'which as shown in Fig. 1 is composed of a series of individual knife 11. T e knife guards project forwardly atan angle oblique y to the line of the travel of themower and form open interstioes 13 between them for the entrance of the grass nerds 12 secured-to a transverse har and their front ends are preferably provided with forwardly and-downwaiidly extending fingers 14 for terstices. y

Each knife guard is formed with a cutguidingthe grass into theinting edge 15 which is adapted to cooperate with a portion of the'cuttinged e of the revolving knife once at each revo ution of the same. To this end the cutting edges 15 conform .substantially at least `for a portion of their le h tothe knife edge ofthe revolving knife and preferably a sufficient number of knife guards are provided to cause each part of the cutting edge ofthe revolving knife to coperate with one of the knife guards. It will be seen that by this arrangement the revolvin knife operating as a conveyer will feed t e grass entering between the knife guards against the cutting edges thereof and then the co erating por tions of the cutting edge of t e revolving knife will once at each revolution coincide therewith and sever the cut in the forward directlon of the travel of the mower. p

On account of 'the shape of the knife guards one edge thereof, the one which is opposed to the lncoming grass may be properly called the anterior edge and the one which .is not opposed thereto and which forms the cutting edge may be called the posterior edge, thus the cutting takes lace against the posterior edge of the ife guards.

It .is not necessary that the cutting edges l5 of the stationary knife guards should exactly conform to the spira cutting edge of the revolvin knife, neither is it necessary that they s ould be of spiral shape to be within the scope of my invention. Thus while in Fig. l the effective forward positions of the cutting edges 15 conform approximately to the shape of the spiral cutting ed e of the revolving knife they are parts o spirals of a lesser pitch, the advan' ass by a shearing.

be that the cutting action between each knife guard and the revolving knife would not take place at once along the' whole edge of.

the knife ard, but graduali beginning at the base o the knife guard. y

In Fig. 4 I show the knife guards formed as integral parts of a concare or of sections of a concave and the edges of these knife guards are wholly formed in verticalplanes conforming approximately only to the shape of the knife guards in Fig. l, many other obvious modications of the knife guards may be made within the spirit of my invention.

The revolving knife may also be variously modified as any of the dierent designs of lscrew-conveyers may be readily adapted for obliquely in a direction substantially corre.

sponding to that of the tangente to the spiral cutting ed e at the points of co-action thereof with sai knife guards.

2. In cutting mechanism, the combination obliquely in a *omnes with a'rotary knife having a s iral cutting edge, of a luralit of fixed nife ards eXtendin n orward y on the underside of said kni e and artially encircling the same obliquely in a 'rection substantially corresponding to that of the tangente to the s iral cuttin edge at the points of coaction t ereof wit l sald knife guards, one edge of each knife guard forming a cutting edge for -said knife adapted to coperate with a vportion of its cutting edge. 1

3. In cutting mechanism, the combination with a rotary knife having a s iral cutting edge, of a luralit of xed nife guards extendin orward y o n the underside of said kni e and artially encircling the same spending to thatl of the tangente to the spiral cutting edge at the points of co-action witn said knife uards, one edge of each knife guard formmga cutting edge with which a portion of the cutting edge of the knife is adapted to coperate, the cutting edges of said knife guards collectively forming a cutting edge corresponding to that of the spiral cutting edge.

In testimony whereof I afIiX my signature in presence 0f two Witnesses.

l JAMES S. LYNCH. Witnesses: I

R. ROY MoYERs, R. L. PRINE.

irection substantially corre 

